Chelating phosphine compounds when bound to metal atoms are generally known to be useful as catalysts. One reaction which uses palladium phosphine catalysts is the coupling of aryl halides with amines for the production of arylamines, as reviewed by Hartwig, SYNLETT, 1997, (4), PG. 329-340. An example of this reaction is the coupling of 4-bromotoluene and diphenylamine to form tolyldiphenylamine: 
Another reaction is which palldium/phosphine catalysts have been used is the Suzuki reaction, where biaryls are produced through the coupling of arylboronic acids and aryl halides, as reviewed by Suzuki, A, J. Orgmet. Chem., 576 (1999), pg. 147. One example of this reaction is the preparation of 2-phenylpyridine from phenylboronic acid and 2-chloropyridine: 
Both of theses products are important classes of compounds used in the manufacture of pharmaceuticals, agrochemicals, advanced materials, polymers and ligands, and much work has been done on their preparation. However, there is an expanding need for stable, easily prepared catalysts that result in good yields and mild reaction conditions.